PHOENIX -- The D-backs will watch Patrick Corbin closely in his Friday start against the Giants and decide after that if the young left-hander needs a break.
Corbin's last two starts have been subpar, and D-backs manager Kirk Gibson has been asked repeatedly whether fatigue is a factor.
"We'll have some special interest to see how Patrick throws," Gibson said. "If he struggles again, then we may look how to get him more rest. Whether it's inserting a sixth guy, or there's a couple of other ideas. For sure it's the one guy we don't want to push him; he's got a lot of innings right now, and we want to make sure we don't hurt him."
Corbin threw a career-high 186 1/3 innings last year between Double-A, Triple-A and the big leagues.
Corbin has thrown 182 2/3 innings this year, and in his last two starts he lasted a combined 10 1/3 innings with 13 earned runs.
"His velocity is maybe down a tick," Gibson said. "His changeup maybe not coming out with the same arm speed."
For his part, Corbin has said he does not feel any added fatigue and that rather it has been a matter of missing his spots and making poor pitches.
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.